Pre-Emergent Herbicides

Pre-emergent herbicides are chemicals that work to stop weeds from sprouting or “emerging” from soil. A pre-emergent herbicide is a great tool to have as part of an overall lawn care program and for weed prevention.

While pre-emergent herbicides don’t guarantee instant gratification, they do work effectively to reduce weeds springing up in your soil when used properly.

Pre-emergent herbicides come either in a water-soluble bag or powder that needs to be mixed with water first (according to the label) before application or they can come in granular form that must be spread using a granular spreader and will require irrigation in order to help the granule release the pre-emergent chemical.

Solutions Pest & Lawn offers professional-quality pre-emergent herbicides for control of target grasses and broadleaf weeds on turf, landscaping, agricultural lands, golf courses, and other areas. Learn more about pre-emergents and how to apply them as well as shop our top pre-emergent products here.

Our Recommendations

Pre-emergent herbicides come in granular and water-soluble forms and can be selective or non-selective. While both are effective formulations, granular pre-emergents are easier to apply and provides less mess. The benefits of liquid solution pre-emergents are that they provide a more even application and you can have more flexibility in terms of the level of concentration. Whatever you choose to kill your weeds depends upon your preference.

We recommend these pre-emergent herbicides for their ease of use and broad labels:

Nitrophos Barricade - Nitrophos Barricade is a granular pre-emergent herbicide. This product is a flexible, broad-spectrum herbicide that can be used on many different grass types. It is used to prevent the germination and growth of grassy and broadleaf weeds in turf and gardens.

Prodiamine 65 WDG - Prodiamine 65WDG is a granulated pre-emergent herbicide. The granules are added to water to create a liquid herbicidal solution. It can be applied to established turfgrass and landscaped areas to control a variety of grass and broadleaf weeds.

User Guide

Tools Needed:

• Personal Protective Equipment (Gloves, Glasses, Mask)
• Granule Spreader

Step 1: Prepare the Treatment Area.

When applying pre-emergents, be sure to aerate the turf first, and not after applying the products. Aeration can break the seal over the ground and around the seeds which makes the pre-emergents less effective. Aeration should be done in early fall and early spring for the best results. This is also a good time to check the temperature of your soil by using a soil thermometer. You’ll want to apply pre-emergent before the soil reaches 55 degrees.

Step 2: Choose your Pre-Emergent Type

Pre-emergents come in liquid, granular, and water-soluble forms. Each product type has its own advantages, so whichever type you end up using depends upon your weed type and personal preference. Granules tend to be easier because they are ready to use and application rates are intended for smaller turf areas, like lawns. But liquid pre-emergents give you the benefit of an even application and flexibility in terms of level of concentration and are great for larger turf areas.

Step 3: Apply Your Pre-Emergent

If you’re going granular, you will first need to calculate the square footage of the treatment area. To do this, measure and multiply the area length times width (length x width = square footage). Nitrophos Barricade is applied from 1.5 to 4 lbs per 1,000 sq. ft. depending on the turf species. Load the granules at the right calibration setting on the spreader and walk over your lawn in two passes via grid-like fashion until your lawn is covered.

For liquid pre-emergents, mix according to the label directions into a backpack or pump sprayer and broadcast the product evenly on your lawn. Using Prodiamine 65 WDG, you would apply 0.185 to 0.83 oz. per 1,000 sq ft. in 0.5 gallon of water per 1,000 sq. ft. Fill your sprayer tank 1/4th of the way with water and then add the appropriate amount of Prodiamine to the spray tank and then add the rest of the required amount of water. Make applications with your sprayer to the treated area on a fan spray nozzle setting for even coverage

Whichever pre-emergent method you select, it is vital that you water the product adequately to get it into the topsoil layer. This does not have to be done immediately, but within the time indicated on the label, usually 1-3 days. Waiting too long exposes the chemical to light and/or heat that will diminish its potency.

Application Timing

Timing is absolutely crucial to the success of your pre-emergent application. The term "pre-emergent" means before the weed has sprung up out of the ground, so if you are applying a pre-emergent herbicide to a weed that has already sprouted, it will be ineffective.

So when should you apply a pre-emergent herbicide? The answer is before your target weed's seeds typically germinate—this is usually in the spring and the fall months. The region of the country where you are located is also a big factor in determining when to apply pre-emergent herbicides.

If you live in the North, depending on the type of weed problem you have, generally we would recommend conducting 2 pre-emergent applications. One in the spring when the ground is no longer frozen and vegetation begins to bloom. The second application should be just before summer.

If You Live in The South, apply a pre-emergent application in mid to late February just before spring really starts to come in. A second treatment should be conducted in mid-may to prepare for the long summer ahead. Finally, a pre-emergent treatment should be applied in the Fall around September or October in preparation for the winter months.

Spring Pre-Emergent Application

When applying Pre-Emergent Herbicides in the Springtime, the goal is to prevent the growth of invasive grassy and broadleaf weeds that grow and thrive in the summer such as crabgrass, foxtail, clover and ragweed.  It is important to wait until the soil reaches the right temperature (55 degrees or higher for 36 to 72 hours) to apply Pre-Emergent Herbicides for best results.

The best timing for that type of weather is between Mid February to May. Use a soil thermometer to help you accurately check the soil temperature so you know the right time to apply.

Fall Pre-Emergent Application

Fall Pre-Emergent Herbicides are meant to prevent annual weeds that typically grow in the winter like Poa Annua, Henbit, and Chickweed. Applications are best conducted before soil temperatures fall below 70 degrees which can be late summer or early fall depending on your regional climate.

Things To Consider

• Not all herbicides are safe to use in certain grass types, so make sure you check the product's label for approved grass types before applying.
• If weeds have already popped up on your soil, pre-emergents will not work. In this case, a post-emergent will need to be used.

Key Takeaways

What are Pre-Emergent Herbicides?

• Pre-Emergents are herbicides used as a protective barrier that prevents weeds from germinating.

What Pre-Emergent Herbicides Do We Recommend?

• Our top recommended pre-emergent herbicides are Prodiamine 65 WDG (spray application) and Nitrophos Barricade (granular spreader application) 

Pre-Emergent Herbicide Consideration

• What type of pre-emergent you use depends on your grass type and the type of weeds that you are trying to control. If you don’t know what type of weeds you have, choose a pre-emergent with a broad label.